FIELD OF THE INVENTION
[0001] The present invention relates to high power RF vacuum devices. More specifically,
it relates to high power electron beam guns designed for alignment with high precision
and the ability to withstand high temperature conditions.
BACKGROUND OF THE INVENTION
[0002] An electron beam gun, or emitter, is an electrical component used in a wide variety
of vacuum devices. Low power electron beam guns, for example, are commonly used in
cathode ray tube (CRT) displays. High power electron beam guns are used in microwave
linear beam vacuum devices such as klystrons and gyrotrons, which have applications
to particle accelerators and nuclear fusion reactors. For example, the International
Thermonuclear Experimental Reactor (ITER) tokamak has an electron cyclotron heating
(ECH) system that uses gyrotrons to inject over 20 MW RF power into the plasma. Unfortunately,
current gyrotrons lack reproducibility of power and efficiency parameters, most likely
due to material variations and variability in the mechanical alignment and precision
of the assembly of its components. Velocity spread has been identified as one of the
main contributors to low gyrotron efficiency. One of the main sources of velocity
spread is the deviation in the geometry and position of the electrodes and cathode.
Small variations in the spacing and position of the electrodes can lead to a significant
increase in the velocity spread and degradation of the device efficiency.
[0003] Current electron beam gun fabrication approaches are based on conventional assembly
techniques; these consist of in-process machining, pinned joints and manual alignment
by the gun builder. Alignment pins are used to locate precisely positioned bores formed
in mating components, along with iterative manual adjustment to align critical features.
Typical electron gun assembly techniques also require clearance between parts to allow
for assembly, which inherently limits the achievable precision of the fabrication
process. Although these fabrication approaches have been successfully employed in
the past for many types of electron guns, improved precision alignment and fabrication
approaches are needed for high power and high frequency applications because the clearances
and tolerances achieved by conventional assembly methods result in detrimental phenomena
such as frequency deviation and velocity spread, which reduce the efficiency of a
device and similarly diminish the consistency of devices which are produced to satisfy
the same specifications. Alignment precision and repeatability at the micron level
are needed to reduce such effects in these high power applications.
[0004] There is thus a need to develop new technologies which would improve the mechanical
alignment of critical gyrotrons components, particularly high power RF electron beam
guns.
[0005] Villanyi in US Pat. No. 4,607,187 refines the conventional approach for the alignment of electron beam gun components.
Oblong and triangular alignment features are formed within the relevant components,
and specially configured precision alignment pins leverage the geometric properties
of these features to provide alignment of the beam-shaping apertures of the components.
While this formulation of a pinned joint technique anticipates gains in the precision
associated with the alignment of an individual electron beam gun, a moderate degree
of complexity is inherent to the subsequent manual alignment utilized in such an alignment
operation, which will lead to variation in the fabrication and performance of identically
constructed devices. Moreover, the slight deviations in form and position between
the nominal design and the actual alignment features of each of the components will
exacerbate the variation of alignment that is associated with this technique, and
therefore the increase the discrepancy in performance between devices.
[0006] Scarpetti et al. in US Pat. No. 5,416,381 discuss a scheme for aligning the components of an electron beam gun while streamlining
the associated assembly process. This methodology is reliant upon the use of ceramic
standoffs as alignment features, which provides desirable electrical isolation of
the cathode from the anode and thereby reduces the number of necessary components.
However, this technique fails to achieve sub-micron precision in the alignment of
these critical device components, citing machining tolerances of ±.0005 in. which
are applied to the alignment bores. As discussed previously, this limited precision
will result in inefficient operation and will incur poor repeatability and corresponding
variation between identical devices.
[0007] A kinematic coupling is a device used in a variety of applications requiring the
alignment of mating components to be precise and repeatable. In order to fully constrain
the respective orientation of two mating components, a kinematic coupling forms deterministic
contact between mating elements of each component. In a typical kinematic coupling,
there are few contact locations, each constraining one degree of freedom between the
mating components. The loading which can be sustained by this approach is fundamentally
limited by the Hertzian contact stresses incurred at the point contact regions where
the elements meet, rendering kinematic couplings generally unsuitable for use in machining
operations and other processes with high loading demands.
[0008] In
US Pat. No. 6,193,430, Culpepper and Slocumb undertake twofold approaches to the problem of increasing
the mechanical loading capacity of a kinematic coupling joint. By implementing a quasi-kinematic
coupling, with spherical convex contact surfaces mating with conical concave depressions,
the regions of point contact in a true kinematic coupling are replaced by line contact
regions, augmenting the load-bearing capacity of the contact in the direction normal
to the conical depressions. In addition, the selection of deformable materials to
form the convex contact surface will allow the opposing mating surfaces to be brought
into contact by the preloading fastening force, allowing the bulk material of the
mating parts to bear load normal to these faces. However, the use of deformable materials
reduces the precision and repeatability of the coupling while diminishing thermal
stability in high temperature applications and rendering such a coupling incompatible
with ultrahigh vacuum environments.
[0009] In addition, there are several other problems with the use of a kinematic coupling
in an electron gun, or even generally in an electron beam device. In an electron gun
there are high electric gradients with DC operating voltages of 100 kV or greater.
There are also very high thermal gradients with electron beam emitter, the cathode,
typically operating at a temperature of 1000 degrees C or higher. Two additional considerations
are that all materials utilized in a gyrotron gun and most other gyrotron gun should
be non-magnetic, as well as that the device undergoes thermal processing "bake-out"
at 500 - 600 degrees C for a period of up to one week. These constraints present significant
technical barriers to the use of kinematic coupling in an electron gun.
SUMMARY OF THE INVENTION
[0010] The aforementioned problems are overcome with an electron beam gun according to claim
1. Preferred embodiments are defined in the dependent claims.
[0011] In one aspect, the present invention provides an electron beam device whose components
are precisely aligned and joined using a kinematic coupling. The kinematic coupling
creates a deterministic interface having six points of contact between the mating
components, which fully constrains the respective orientation of the mating components.
Convex coupling elements are fabricated to withstand concentrated Hertzian contact
stresses in high temperature applications. The coupling elements are individually
joined to the first mating component in a manner which is compatible with ultra-high
vacuum environments and which enables repeatable alignment and use in machining operations
through high mechanical stiffness. Machining of mating components in the final assembly
position ensures precise alignment in an electron beam device. The present invention
provides an electron beam device having at least one kinematic coupling with very
high precision and repeatability. The kinematic coupling deterministically locates
and aligns one electron beam device component with respect to a mating component.
It retains functionality in high temperature conditions and has compatibility with
ultrahigh vacuum environments.
[0012] Preferably, the kinematic coupling uses a novel integrated structure. Usually the
high voltage insulator (ceramic assembly) of an electron gun is a separate assembly,
used only to provide electrical insulation (100 kV or higher) and provide a vacuum
envelope. In embodiments of the present invention, the high voltage ceramic becomes
a structural component of the electron gun and forms the base of the kinematic coupling
in addition to the high voltage insulator. This integrated function is a unique physical
attribute of embodiments of the invention, and it provides for a more compact design
and reduced high voltage region, decreasing the potential of electric break down which
is one of the significant issues with electron guns and devices.
[0013] The kinematic coupling elements are fixed to the electron beam gun components using
a unique direct metal to ceramic bonding process using brazing. This process involves
using a high temperature active metal brazing alloy (at over 1000 degrees C) to bond
ceramic coupling elements to non-ductile rigid base metals. The ceramic elements are
on the order of 1/2 inch diameter. The use of high strength ceramics, e.g., silicon
nitride, provides another key feature. Most conventional ceramic brazing is performed
using aluminum oxide ceramics. Direct bonding conventionally uses a lower melting
braze material at under 800 degrees C, containing silver which is not desirable and
also use thermal expansion matched metals, e.g., kovar (a nickel-cobalt ferrous alloy).
However, kovar is magnetic, making it not suitable for use in electron guns. Also,
these thermally expansion matched metals only work to a braze temperature of about
800 degrees, above that the thermal expansion between ceramics and the base metal
starts to diverge and the stresses tend to become too high.
[0014] Embodiments of the present invention overcome these problems through the use of high
strength ceramics in an electron gun and direct metal to ceramic bonding process using
a brazing process with a high temperature active metal brazing alloy. In addition,
a unique braze joint geometry limits the braze stresses in the ceramic. The geometry
is a counterbored shape with a groove along the outer diameter of the counterbore.
[0015] The techniques of the present invention allow the fabrication of very high precision
vacuum device components for applications such as gyrotron, with the potential to
dramatically improve performance. A very high precision electron gun will produce
a higher quality electron beam, by reducing velocity spread and enabling additional
gun design optimization. Furthermore, by utilizing very high precision electron guns
in gyrotrons the reproducibility between devices would be significantly improved.
[0016] Using the techniques of the present invention, electron gun components such as cathode
and electrodes may simply be stacked using precision kinematic coupling interfaces.
No additional alignment or adjustment procedures are required, resulting in the realization
of significant labor time and cost savings. Thus this technology can significantly
improve the electron gun performance while at the same time reducing assembly costs
and time.
[0017] The present technology has the potential to be broadly adopted across the vacuum
electronics industry. The benefits of the technology, reduced cost and improved precision,
would drive interest to expand to additional applications in klystrons, accelerators
and THz devices.
[0018] In one aspect, the invention provides an electron beam gun that includes a first
component, which is a non-ductile rigid metal, joined to a second component by a fixed
kinematic coupling. The fixed kinematic coupling includes convex ceramic elements
composed of silicon nitride or silicon carbide directly bonded to the first component
using a high temperature active metal brazing alloy having a melting temperature higher
than 970 degrees C, and concave grooves in the second component arranged to mate with
the convex ceramic elements. Preferably, the second component is a ceramic. The first
non-ductile rigid metal component may be, for example, a beam shaping focus electrode
or cathode assembly, and the second component may be a gun stem.
[0019] In one aspect, the invention provides an electron beam gun for a high power RF vacuum
device. The device includes a cathode stem and an anode assembly, both joined to a
base. The anode assembly includes an anode, and the cathode stem includes a gun stem,
a fixed kinematic coupling, a cathode assembly, and a beam shaping focus electrode
(having inner and outer electrodes). The cathode assembly has a cathode housing (support
sleeve) made of a first non-ductile rigid metal material. The cathode assembly may
also have a tungsten emitter, tungsten heater, heat shields, and ceramic heater potting.
The beam shaping focus electrode is similarly composed of a second non-ductile rigid
metal material. The non-ductile rigid metal materials are preferably materials that
retain an elastic modulus above 100 GPa at a temperature of 1000 degrees C, for example,
stainless steel or molybdenum.
[0020] The cathode assembly and beam shaping focus electrode are joined to the gun stem
using a fixed kinematic coupling. The kinematic coupling includes high strength ceramic
elements directly bonded to the beam shaping focus electrode and to the cathode housing
using a high temperature active metal brazing alloy. The kinematic coupling also includes
V-grooves in the gun stem arranged to mate with the high strength ceramic elements.
[0021] In a preferred embodiment, the kinematic coupling has three high strength ceramic
elements directly bonded to the cathode housing and three high strength ceramic elements
directly bonded to the focus electrode. Both the focus electrode and cathode assembly
thus sit in a common kinematic coupling base (i.e. their ceramic elements all mate
with the same V-grooves in the gun stem, which is preferably also a high strength
ceramic). The high temperature active metal brazing alloy is preferably an active
metal brazing alloy that has a melting temperature higher than 970 degrees C. The
high temperature active metal brazing alloy preferably does not contain silver or
nickel-cobalt ferrous alloy. The high temperature active metal brazing alloy may be,
for example, an alloy of Ti, Cu-Ti, Au-Ti, Zr or Hf .
[0022] The beam shaping focus electrode may include an inner beam shaping electrode and
an outer beam shaping electrode. The anode assembly may be joined to the base using
a fixed kinematic coupling or other precision joint. Alternatively, the anode may
be joined to a cylindrical ceramic housing of the anode assembly using a fixed kinematic
coupling.
[0023] The kinematic coupling preferably has three V-grooves in the gun stem positioned
to mate with the high strength ceramic elements that are bonded to the cathode assembly
and focusing electrode. The high strength ceramic elements preferably have flexural
strength above 500 MPa. The high strength ceramic elements, for example, may be composed
of silicon nitride or silicon carbide. The kinematic coupling preferably provides
electrical insulation of more than 100 kV between the anode assembly and the cathode
assembly, while also providing more than 100 kV between the anode assembly and the
beam shaping focus electrode. The kinematic coupling preferably also provides electrical
insulation of more than 1 kV between the cathode assembly and the beam shaping focus
electrode.
[0024] The electron beam gun may be part of a high power RF vacuum device such as, for example,
a gyrotron, klystron, or magnetron.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025]
Figs. 1A-C are cut-away perspective views of an electron beam gun for a high power
RF vacuum device, according to an embodiment of the invention, where Figs. 1B and
1C are detail views of coupling components and cathode assembly components, respectively,
of Fig. 1A.
Figs. 2A-B are two perspective views of a cathode stem, according to an embodiment
of the invention.
Figs. 3A-B are cross-sectional views of an electron beam gun, according to an embodiment
of the invention, where Fig. 3B is a detail view of cathode assembly components in
Fig. 3A.
Figs. 4A-B are two perspective views of a kinematic coupling, according to an embodiment
of the invention, where Fig. 4B is a cut-away exploded view.
Fig. 5 is a cross-sectional detail view of a portion of a kinematic coupling showing
convex coupling element mated with concave groove feature with two points of contact,
according to an embodiment of the invention.
Figs. 6A-F show side and perspective views of differently shaped contact surfaces
of convex coupling elements, according to three embodiments of the invention.
DETAILED DESCRIPTION
[0026] Electron beam devices according to embodiments of the present invention feature kinematic
couplings, e.g., with a ball-in-groove joint where three balls on one component mate
with three grooves on the second component with small area contacts. The kinematic
couplings are deterministic: They only make contact at a number of points equal to
the number of degrees of freedom that are to be restrained. Being deterministic makes
performance predictable and also helps to reduce design and manufacturing costs. Kinematic
couplings have traditionally been used in instrument design where the loads typically
are relatively light and static. Through the use of well- engineered contact areas
and/or advanced ceramic materials they are can be made quite robust and suitable for
demanding applications requiring high stiffness and load capacity.
[0027] Figs. 1A-C are cut-away perspective views of an electron beam gun for a high power
RF vacuum device according to an embodiment of the invention. As shown in Fig. 1A,
it includes a cathode stem comprising a base 12, gun stem 10 joined to the base 12,
and beam shaping focus electrodes (outer focus electrode 6 and inner focus electrode
7). It also includes a cathode assembly, labeled A and B, which are detailed in Figs.
1B-C, respectively. The cathode assembly has a tungsten cathode/emitter 1, tungsten
heater 2, ceramic heater potting 3, heat shields 4, and a cathode housing (support
sleeve) 5. The cathode housing 5 is made of a non-ductile rigid metal material. The
beam shaping focus electrode 6 and 7 is similarly composed of a second non-ductile
rigid metal material. The cathode assembly is joined to the the gun stem 10 using
a fixed kinematic coupling element 8a which mates with V-groove 9. The beam shaping
focus electrode (which includes outer electrode 6 and inner electrode 7) is joined
to gun stem 10 using fixed kinematic coupling element 8b which also mates with V-groove
9. The kinematic coupling preferably has three high strength ceramic elements directly
bonded to the beam shaping focus electrode 6 using a high temperature active metal
brazing alloy. The kinematic coupling preferably also has three high strength ceramic
elements directly bonded to the cathode assembly (e.g., to the cathode housing 5)
using a high temperature active metal brazing alloy. The kinematic coupling has three
V-grooves 9 in the gun stem positioned to mate with the three high strength ceramic
elements. In a preferred implementation, the gun stem is ceramic and acts as a high
voltage ceramic assembly. The electron beam gun may also include an anode assembly
that includes a cylindrical housing 13 joined to the base 12, and an anode 11 joined
to the cylindrical housing 13. The cylindrical housing may be metal. In an alternate
embodiment, the cylindrical housing 13 may be ceramic, in which case it is a high
voltage ceramic assembly, and the gun stem 10 may be a metal.
[0028] Fig. 3A is a cross-sectional view of the same device as shown in Fig. 1A, and Fig.
3B is a detail view of cathode assembly components, labeled C in Fig. 3A.
[0029] Figs. 2A-B are two views of the cathode stem. As shown in Fig. 2A, the cathode stem
has a base 12, gun stem 10 joined to the base 12, beam shaping focus electrode (including
outer focus electrode 6 and inner focus electrode 7), and a cathode/emitter 1 between
the two electrodes 6 and 7. As shown in the exposed view of Fig. 2B, the gun stem
has at its top three coupling V-grooves 9, each with its axis oriented radially. Matching
coupling elements 8, each preferably with a hemispherical shape, are attached to cathode
assembly and focus electrode and are positioned to align with the V-grooves 9 to form
a kinematic coupling.
[0030] A key feature of the electron beam gun is the kinematic coupling joint, which includes
grooves and matching coupling elements. Through the use of silicon nitride or other
high strength ceramics, the coupling elements thereby are suitable for use as voltage
offset elements and are mechanically capable of withstanding concentrated Hertzian
contact stresses in high-temperature applications. A direct metal-to-ceramic braze
is a permanent and rigid joint which is compatible with UHV environments and which
enables repeatable alignment and in-process machining use through high mechanical
stiffness.
[0031] An illustration of a kinematic coupling in two configurations according to an embodiment
of the invention is shown in Figs. 4A-B. The coupling has top component 46 aligned
coaxially with a base component 47, each having the shape of an annulus. Three coupling
bolts 43, 44, 45, oriented parallel to the axis of the top and base components, hold
the two components together. Top component 46 has counterbore holes (e.g., hole 52
for bolt 43 and hole 53 for bolt 44) and base component 47 has holes aligned with
them (e.g., hole 50 for bolt 43 and hole 51 for bolt 44). The base component 47 has
three V-grooves 40, 41, 42 designed to mate with corresponding hemispherical coupling
elements brazed to the top component 46 (e.g., hemispherical coupling element 48 mates
with V-groove 41 and hemispherical coupling element 49 mates with V-groove 42). The
three V-grooves are preferably oriented radially 120 degrees apart from each other.
[0032] More generally, the kinematic coupling has top and base electron beam device components
46, 47 to be mated, as shown in Fig. 5. A top component 46 has a plurality of convex
coupling features (e.g., hemispherical coupling elements 48) and a base component
47 has a plurality of concave coupling elements (e.g., grooves 41) that are formed
in or joined to the base mating component 47 and are designed to receive and deterministically
align the top mating component with respect to the base mating component when in contact
with the plurality of convex coupling elements 48. A plurality of fastening elements
(e.g., coupling bolts, see Fig. 4B) hold the two components in static contact at deterministic
points XI, X2. The plurality of concave coupling features 41 is preferably formed
within or joined to the base coupling component 47 with planar contact surfaces to
form an arrayed V-groove configuration.
[0033] The plurality of convex coupling elements 48 preferably provide electrical insulation
between the coupling features. For example, they are preferably fabricated from a
ceramic such as silicon nitride. The plurality of convex coupling elements 48 are
individually joined to the top component 46 using a direct metal-to-ceramic bond.
[0034] The plurality of convex coupling elements 48 generally may a convex shape as a contact
surface. For example, Figs. 6A-B show side and perspective views, respectively, of
a truncated cone shaped contact surface. Figs. 6C-D show side and perspective views,
respectively, of a truncated triangular prism shaped contact surface. Figs. 6E-F show
side and perspective views, respectively, of a hemispherical shaped contact surface.
It will be evident that these examples are not limiting, and that many other convex
shapes may be used for the contact surface.
[0035] In the gun region there are high electric and thermal gradients, and the coupling
also must meet the general ultra-high vacuum requirements for good electron beam emission
and transmission.
[0036] Ceramic coupling elements are preferably used on the ball side of the kinematic coupling
in order to accommodate Hertzian contact stresses. The ceramic coupling elements are
preferably made of a ceramic material with high strength, fracture toughness, and
strength at elevated temperatures. Specifically, the high strength ceramic elements
preferably have flexural strength above 500 MPa. The high strength ceramic elements,
for example, may be composed of silicon nitride or silicon carbide.
[0037] The ceramic coupling elements are permanently and rigidly attached to the base metal
to allow for precision alignment. For this purpose, a braze joint design was developed,
which allowed the direct bonding of silicon nitride ceramic elements to various metals.
Brazing silicon nitride (with its low coefficient of thermal expansion) to metals
such as stainless steel (with much higher rates of thermal expansion) presents a challenge
due to stresses which result from the thermal expansion differential. The inventor
has discovered that with the high strength silicon nitride ceramics it is possible
to achieve a direct bond without the need for an intermediate ductile metal layer,
as frequently utilized in ceramic assemblies. A finite element simulation shows the
resultant principal stresses in a silicon nitride coupling element when brazed to
a stainless steel base has a peak tensile stress of 680 MPa, which is approximately
20% below the 800 MPa tensile strength of the silicon nitride ceramic. For the braze
process a high temperature melting active metal braze alloy is utilized. The result
is a high stiffness mechanical joint between the ceramic and the base metal. The high
temperature active metal brazing alloy is preferably an active metal brazing alloy
that has a melting temperature higher than 970 degrees C. It preferably does not contain
silver or nickel-cobalt ferrous alloy. The high temperature active metal brazing alloy
may be, for example, an alloy of Ti, Cu-Ti, Au-Ti, Zr or Hf.
[0038] The cathode housing (support sleeve) is made of a non-ductile rigid metal material.
The beam shaping focus electrode is similarly composed of a non-ductile rigid metal
material. Such a non-ductile rigid metal material may be defined for the purposes
of the present description has a material that retains an elastic modulus above 100
GPa at a temperature of 1000 degrees C. For example, the non-ductile rigid metal material
may be molybdenum or stainless steel. In a preferred embodiment, the gun stem is made
of a stainless steel and the focus electrode is made of molybdenum.
[0039] The use of precision couplings between individual components of the gun provides
new opportunities for simplifying and improving the design of electron guns. The kinematic
coupling allows the use of dissimilar materials across mechanical interfaces, whereas
in a traditional type of electron gun these key joint are welded and the joint materials
must be similar or weld compatible. The kinematic coupling allows for the key individual
components such as the focus electrode to be entirely fabricated from the most suitable
material for electron beam shaping; interface and mounting are handled by the kinematic
coupling and are no longer a limiting factor in the overall gun design.
[0040] The inner and outer focus electrodes are near-net-shape molybdenum pieces with sufficient
extra material on the exterior surface to allow for high precision final machining.
After the successful braze of the focus electrodes, the focus electrodes are mounted
onto the cathode stem and final machined. The ease and precision of assembly enabled
by the kinematic coupling allows the focus electrodes to be machined directly on the
cathode stem, preserving the mounting configuration used in a gyrotron device.
[0041] For the cathode, a custom cathode base may be fabricated, which together with associated
tooling specifically engineered for this application allows cathode vendors to furnish
a complete cathode assembly for the gun. The cathode assembly mates to the electron
gun stem with its own coupling.
[0042] It will be evident from those skilled in the art that the teachings and principles
of the present invention do not limit an electron gun design to the particular design
shown in the embodiments for purposes of illustration. Different mechanical gun designs
are possible for different specific purposes and applications without departing from
scope of the invention as defined in appended claim 1. The designs may differ, for
example, in the location of the kinematic coupling. Embodiments may also include additional
kinematic couplings, e.g., between the inner focus electrode and the cathode assembly,
and/or between the anode assembly and the base. Different designs may be thermally
analyzed using finite element analysis software. Based on manufacturing considerations
and thermal performance, appropriate specific designs may be selected.
1. An electron beam gun for a high power RF vacuum device comprising:
a base (12), a cathode stem, and an anode assembly; wherein the cathode stem and anode
assembly are joined to the base;
wherein the anode assembly comprises an anode (11);
wherein the cathode stem comprises a gun stem (10), a fixed kinematic coupling (8a,
8b), a cathode assembly, and a beam shaping focus electrode (6, 7),
wherein the cathode assembly comprises a cathode housing made of a first non-ductile
rigid metal material;
wherein the beam shaping focus electrode (6, 7) is composed of a second non-ductile
rigid metal material,
wherein the cathode assembly and beam shaping focus electrode (6, 7) are joined to
the gun stem (10) using the fixed kinematic coupling (8a, 8b),
wherein the fixed kinematic coupling (8a, 8b) comprises high strength ceramic elements
directly bonded to the beam shaping focus electrode and cathode housing using a high
temperature active metal brazing alloy,
wherein the kinematic coupling comprises V-grooves in the gun stem (10) to mate with
the high strength ceramic elements.
2. The electron beam gun of claim 1 wherein the beam shaping focus electrode (6, 7) comprises
an inner beam shaping focus electrode and an outer beam shaping focus electrode, wherein
the outer beam shaping focus electrode (6, 7) is joined to the gun stem (10) using
the fixed kinematic coupling.
3. The electron beam gun of claim 1 wherein the anode assembly is joined to the base
using the fixed kinematic coupling (8a, 8b).
4. The electron beam gun of claim 1 wherein the first non-ductile rigid metal material
is a first material that retains an elastic modulus above 100 GPa at a temperature
of 1000 degrees C, and wherein the second non-ductile rigid metal material is a second
material that retains an elastic modulus above 100 GPa at a temperature of 1000 degrees
C.
5. The electron beam gun of claim 1 wherein the gun stem (10) is composed of a high strength
ceramic.
6. The electron beam gun of claim 1 wherein the first non-ductile rigid metal material
is stainless steel or molybdenum, and wherein the second non-ductile rigid metal material
is stainless steel or molybdenum.
7. The electron beam gun of claim 1 wherein the high temperature active metal brazing
alloy is an active metal brazing alloy that has a melting temperature higher than
970 degrees C.
8. The electron beam gun of claim 1 wherein the high temperature active metal brazing
alloy is an alloy of Ti, Cu-Ti, Au-Ti, Zr or Hf .
9. The electron beam gun of claim 1 wherein the high strength ceramic elements have flexural
strength above 500 MPa.
10. The electron beam gun of claim 1 wherein the high strength ceramic elements are composed
of silicon nitride or silicon carbide.
11. The electron beam gun of claim 1 wherein the kinematic coupling provides electrical
insulation of more than 100 kV between the cathode assembly and the anode assembly.
12. The electron beam gun of claim 1 wherein the kinematic coupling provides electrical
insulation of more than 100 kV between the beam shaping focusing electrode and the
anode assembly.
13. The electron beam gun of claim 1 wherein the kinematic coupling provides electrical
insulation of more than 1 kV between the beam shaping focusing electrode and the cathode
assembly.
14. The electron beam gun of claim 1 wherein the cathode assembly further comprises a
tungsten emitter, tungsten heater, heat shields, and ceramic heater potting.
15. The electron beam gun of claim 1 wherein the high power RF vacuum device is a gyrotron,
klystron, or magnetron.
1. Elektronenstrahlkanone für eine Hochleistungs-HF-Vakuumvorrichtung, Folgendes umfassend:
eine Basis (12), einen Kathodenschaft und eine Anodenanordnung; wobei der Kathodenschaft
und die Anodenanordnung mit der Basis verbunden sind;
wobei die Anodenanordnung eine Anode (11) umfasst;
wobei der Kathodenschaft einen Kanonenschaft (10), eine feste kinematische Kopplung
(8a, 8b), eine Kathodenanordnung und eine strahlformende Fokussierungselektrode (6,
7) umfasst,
wobei die Kathodenanordnung ein Kathodengehäuse umfasst, das aus einem ersten nicht
duktilen starren Metallmaterial gefertigt ist;
wobei die strahlformende Fokussierungselektrode (6, 7) aus einem zweiten nicht duktilen
starren Metallmaterial gebildet ist,
wobei die Kathodenanordnung und die strahlformende Fokussierungselektrode (6, 7) mit
dem Kanonenschaft (10) unter Verwendung der festen kinematischen Kopplung (8a, 8b)
verbunden sind,
wobei die feste kinematische Kopplung (8a, 8b) hochfeste Keramikelemente umfasst,
die unter Verwendung einer hochtemperaturaktiven Hartlötlegierung direkt an die strahlformende
Fokussierungselektrode gehaftet sind,
wobei die kinematische Kopplung V-Nuten in dem Kanonenschaft (10) umfasst, die mit
den hochfesten Keramikelementen zusammenpassen.
2. Elektronenstrahlkanone nach Anspruch 1, wobei die strahlformende Fokussierungselektrode
(6, 7) eine innere strahlformende Fokussierungselektrode und eine äußere strahlformende
Fokussierungselektrode umfasst, wobei die äußere strahlformende Fokussierungselektrode
(6, 7) mit dem Kanonenschaft (10) unter Verwendung der festen kinematischen Kopplung
verbunden ist.
3. Elektronenstrahlkanone nach Anspruch 1, wobei die Anodenanordnung unter Verwendung
der festen kinematischen Kopplung (8a, 8b) mit der Basis verbunden ist.
4. Elektronenstrahlkanone nach Anspruch 1, wobei das erste nicht duktile starre Metallmaterial
ein erstes Material ist, das ein Elastizitätsmodul über 100 GPa bei einer Temperatur
von 1000 Grad Celsius bewahrt, und wobei das zweite nicht duktile starre Metallmaterial
ein zweites Material ist, das ein Elastizitätsmodul über 100 GPa bei einer Temperatur
von 1000 Grad Celsius bewahrt.
5. Elektronenstrahlkanone nach Anspruch 1, wobei der Kanonenschaft (10) aus hochfester
Keramik gebildet ist.
6. Elektronenstrahlkanone nach Anspruch 1, wobei das erste nicht duktile starre Metallmaterial
Edelstahl oder Molybdän ist, und wobei das zweite nicht duktile starre Metallmaterial
Edelstahl oder Molybdän ist.
7. Elektronenstrahlkanone nach Anspruch 1, wobei die hochtemperaturaktive Hartlötlegierung
eine aktive Hartlötlegierung ist, die eine Schmelztemperatur von über 970 Grad Celsius
aufweist.
8. Elektronenstrahlkanone nach Anspruch 1, wobei die hochtemperaturaktive Hartlötlegierung
eine Legierung aus Ti, Cu-Ti, Au-Ti, Zr oder Hf ist.
9. Elektronenstrahlkanone nach Anspruch 1, wobei die hochfesten Keramikelemente eine
Biegefestigkeit von über 500 MPa aufweisen.
10. Elektronenstrahlkanone nach Anspruch 1, wobei die hochfesten Keramikelemente aus Siliziumnitrid
oder Siliziumkarbid gebildet sind.
11. Elektronenstrahlkanone nach Anspruch 1, wobei die kinematische Kopplung eine elektrische
Isolierung von über 100 kV zwischen der Kathodenanordnung und der Anodenanordnung
bereitstellt.
12. Elektronenstrahlkanone nach Anspruch 1, wobei die kinematische Kopplung eine elektrische
Isolierung von über 100 kV zwischen der strahlformenden Fokussierungselektrode und
der Anodenanordnung bereitstellt.
13. Elektronenstrahlkanone nach Anspruch 1, wobei die kinematische Kopplung eine elektrische
Isolierung von über 1 kV zwischen der strahlformenden Fokussierungselektrode und der
Kathodenordnung bereitstellt.
14. Elektronenstrahlkanone nach Anspruch 1, wobei Kathodenanordnung ferner einen Wolfram-Emitter,
eine Wolfram-Heizung, Heizschilder und keramischen Isolierverguss umfasst.
15. Elektronenstrahlkanone nach Anspruch 1, wobei die Hochleistungs-HF-Vakuumvorrichtung
ein Gyrotron, Klystron oder Magnetron ist.
1. Canon à faisceau d'électrons pour un dispositif à vide RF haute puissance comprenant
:
une base (12), une tige de cathode, et un ensemble anode ; dans lequel la tige de
cathode et l'ensemble anode sont joints à la base ;
dans lequel l'ensemble anode comprend une anode (11) ;
dans lequel la tige de cathode comprend une tige de canon (10), un couplage cinématique
fixe (8a, 8b), un ensemble cathode, et une électrode de focalisation de mise en forme
de faisceau (6, 7),
dans lequel l'ensemble cathode comprend un boîtier de cathode fait d'un premier matériau
métallique rigide non ductile ;
dans lequel l'électrode de focalisation de mise en forme de faisceau (6, 7) est composée
d'un second matériau métallique rigide non ductile,
dans lequel l'ensemble cathode et l'électrode de focalisation de mise en forme de
faisceau (6, 7) sont joints à la tige de canon (10) en utilisant le couplage cinématique
fixe (8a, 8b),
dans lequel le couplage cinématique fixe (8a, 8b) comprend des éléments en céramique
à haute résistance directement liés à l'électrode de focalisation de mise en forme
de faisceau et au boîtier de cathode en utilisant un alliage de brasage métallique
actif à haute température,
dans lequel le couplage cinématique comprend des rainures en V dans la tige de canon
(10) pour s'accoupler avec les éléments en céramique à haute résistance.
2. Canon à faisceau d'électrons selon la revendication 1, dans lequel l'électrode de
focalisation de mise en forme de faisceau (6, 7) comprend une électrode de focalisation
de mise en forme de faisceau interne et une électrode de focalisation de mise en forme
de faisceau externe, dans lequel l'électrode de focalisation de mise en forme de faisceau
externe (6, 7) est jointe à la tige de canon (10) en utilisant le couplage cinématique
fixe.
3. Canon à faisceau d'électrons selon la revendication 1, dans lequel l'ensemble anode
est joint à la base en utilisant le couplage cinématique fixe (8a, 8b).
4. Canon à faisceau d'électrons selon la revendication 1, dans lequel le premier matériau
métallique rigide non ductile est un premier matériau qui conserve un module d'élasticité
supérieur à 100 GPa à une température de 1 000 degrés C, et dans lequel le second
matériau métallique rigide non ductile est un second matériau qui conserve un module
d'élasticité supérieur à 100 GPa à une température de 1 000 degrés C.
5. Canon à faisceau d'électrons selon la revendication 1, dans lequel la tige de canon
(10) est composée d'une céramique à haute résistance.
6. Canon à faisceau d'électrons selon la revendication 1, dans lequel le premier matériau
métallique rigide non ductile est un acier inoxydable ou du molybdène, et dans lequel
le second matériau métallique rigide non ductile est un acier inoxydable ou du molybdène.
7. Canon à faisceau d'électrons selon la revendication 1, dans lequel l'alliage de brasage
métallique actif à haute température est un alliage de brasage métallique actif qui
présente une température de fusion supérieure à 970 degrés C.
8. Canon à faisceau d'électrons selon la revendication 1, dans lequel l'alliage de brasage
métallique actif à haute température est un alliage de Ti, Cu-Ti, Au-Ti, Zr ou Hf.
9. Canon à faisceau d'électrons selon la revendication 1, dans lequel les éléments en
céramique à haute résistance présentent une résistance à la flexion supérieure à 500
MPa.
10. Canon à faisceau d'électrons selon la revendication 1, dans lequel les éléments en
céramique à haute résistance sont composés de nitrure de silicium ou de carbure de
silicium.
11. Canon à faisceau d'électrons selon la revendication 1, dans lequel le couplage cinématique
fournit une isolation électrique de plus de 100 kV entre l'ensemble cathode et l'ensemble
anode.
12. Canon à faisceau d'électrons selon la revendication 1, dans lequel le couplage cinématique
fournit une isolation électrique de plus de 100 kV entre l'électrode de focalisation
de mise en forme de faisceau et l'ensemble anode.
13. Canon à faisceau d'électrons selon la revendication 1, dans lequel le couplage cinématique
fournit une isolation électrique de plus de 1 kV entre l'électrode de focalisation
de mise en forme de faisceau et l'ensemble cathode.
14. Canon à faisceau d'électrons selon la revendication 1, dans lequel l'ensemble cathode
comprend en outre un émetteur en tungstène, un élément chauffant en tungstène, des
écrans thermiques et un enrobage d'élément chauffant en céramique.
15. Canon à faisceau d'électrons selon la revendication 1, dans lequel le dispositif à
vide RF haute puissance est un gyrotron, un klystron ou un magnétron.